<p>This dissertation shows the use of Constructal law to find the relation between the morphing of the system configuration and the improvements in the global performance of the complex flow system. It shows that the better features of both flow and heat transfer architecture can be found and predicted by using the constructal law in energy systems. Chapter 2 shows the effect of flow configuration on the heat transfer performance of a spiral shaped pipe embedded in a cylindrical conducting volume. Several configurations were considered. The optimal spacings between the spiral turns and spire planes exist, such that the volumetric heat transfer rate is maximal. The optimized features of the heat transfer architecture are robust. Chapter 3 shows the heat transfer performance of a helically shaped pipe embedded in a cylindrical conducting volume. It shows that the optimized features of the heat transfer architecture are robust with respect to changes in several physical parameters. Chapter 4 reports analytically the formulas for effective permeability in several configurations of fissured systems, using the closed-form description of tree networks designed to provide flow access. The permeability formulas do not vary much from one tree design to the next, suggesting that similar formulas may apply to naturally fissured porous media with unknown precise details, which occur in natural reservoirs. Chapter 5 illustrates a counterflow heat exchanger consists of two plenums with a core. The results show that the overall flow and thermal resistance are lowest when the core is absent. Overall, the constructal design governs the evolution of flow configuration in nature and energy systems.</p> / Dissertation

Currently, in the United States, on-road vehicles are primarily powered by petroleum fuels (gasoline and diesel). These vehicles have caused serious climate change effects from emissions of greenhouse gas (GHG) and health and environmental impacts from criteria air pollutant (CAP). The recent success of shale gas development has brought industry interest in using natural gas to power on-road vehicles. In addition to low costs and wide availability of this national fuel source, natural gas is a common feedstock to produce alternative fuels. The question arises of whether using natural gas for transportation could help or hinder the environment. In this dissertation, I study the economic and environmental effects of a wide range of natural gas fuel pathways for a selection of light duty (LDV) and medium and heavy duty (MHDV) vehicle types. I choose to focus on two environmental metrics: GHGs and CAPs emitted over the life cycle of each potential pathway for natural gas use. First in Chapters 2 and 3, I use life-cycle analysis to understand the emissions of GHGs from different natural gas pathway for LDVs and MHDVs. Then in Chapter 4 I focus on the CAP emissions from these vehicles. Overall, I find that none of the natural gas pathways eliminate life cycle air emissions. In fact, only a few pathways reduce life cycle GHG emissions and/or life cycle air pollution damages compared to baseline petroleum fuels (gasoline for light-duty vehicles (LDVs) and diesel for heavy-duty vehicles (HDVs)). For the cases of light duty vehicles (LDVs) and transit buses, battery electric vehicles (BEVs) powered by natural gas-based electricity provide significant reduction in life cycle GHG emissions and life cycle air pollution damages (for almost all counties) compared to the baseline petroleum fuels. However, the actual electricity that charges BEVs may not be natural gas-based electricity in most parts of the U.S. When powered by U.S. grid electricity (using average emission factors for 2010 and 2014), BEVs reduce life cycle GHG emissions to a lesser extent but increase life cycle air pollution damages significantly. Compressed natural gas (CNG), while reducing GHG emissions and CAP emissions (except CO) at tailpipe, are more likely to increase life cycle GHG emissions and increase life cycle air pollution damages in the majority of U.S. counties. For heavy-duty trucks, CNG sparking-ignition (SI) trucks and liquefied natural gas (LNG) high-pressure direct ignition (HPDI) trucks have mixed environmental impacts. While they are unlikely to reduce life cycle GHG emissions compared to diesel, they reduce life cycle air pollution damages in 76-99% of U.S. counties for local-haul tractor-trailers and in 32-71% of U.S. counties for long-haul tractor-trailers. In Chapters 5 and 6, I examine the economic impacts of natural gas fuel pathways for two vehicle types, tractor-trailers and transit buses. I study the economic feasibility of a national natural gas refueling infrastructure for long-haul trucks in U.S., which is a prerequisite for natural gas tractor-trailers. I find that a transition to natural gas fuels in long-haul trucks is more expensive when the shares of natural gas trucks are below 5% because of low refueling demands and over-capacity of the refueling infrastructure to ensure network coverage. At higher shares of natural gas trucks, both the total refueling capacity and the net economic benefits of the national refueling infrastructure increase almost linearly as adoption increases. Finally, in Chapter 6, I provide an economic-technology assessment for transit buses by considering both life cycle ownership costs and life cycle social costs due to GHG emissions and CAP emissions. Transit buses are early adopters of alternative fuel technologies because of funding supports and operation characteristics (such as high fuel consumption and private refueling infrastructure). I find that the availability of external funding is crucial for transit agencies to adopt any alternative fuel option. Without external funding, only rapid-charging battery electric buses (BEBs) have lower ownership & social costs than conventional diesel buses. When external funding is available to reduce bus purchase costs by 80%, BEBs become much more cost-effective. In this case, life cycle ownership and social costs of BEBs are 37-43% lower than conventional diesel buses. Including life cycle social costs does not change the ranking of alternative fuel options. The findings in this dissertation suggest different strategies of using natural gas for different vehicle markets. Natural gas is best used in electric power generation than to produce gaseous or liquid fuels for powering on-road LDVs. The use of CNG and LNG for heavy-duty trucks may continue as there are less alternative fuel options but issues such as methane leakage should be addressed to avoid important climate change effect. Finally, natural gas-based transportation fuels can at best partially mitigate climate change or air pollution damages, so other mitigation strategies in the transportation sector are ultimately needed to achieve sustainable transportation.

The United States leads the world in per capita production of Municipal Solid Waste (MSW), generating approximately 200 million tons per year. By 2000 A.D. the US EPA predicts a 20% rise in these numbers. Currently the major strategies of MSW disposal are (i) landfill and (ii) incineration. The amount of landfill space in the US is on a rapid decline. There are -10,000 landfill sites in the country, of which only 65-70% are still in use. The Office of Technology Assessment (OTA) predicts an 80% landfill closure rate in the next 20 years. The development of a viable energy resource from MSW, in the form of densified Refuse Derived Fuel (dRDF), provides solutions to the problems of MSW generation and fossil fuel depletions. Every 2 tons of MSW yields approximately 1 ton of dRDF. Each ton of dRDF has an energy equivalent of more than two barrels of oil. At current production rates the US is "throwing away" over 200,000,000 barrels of oil a year. In order to be considered a truly viable product dRDF must be extensively studied; in terms of it's cost of production, it's combustion properties, and it's potential for environmental pollution. In 1987 a research team from the University of North Texas, in conjunction with the US DOE and Argonne National Laboratory (ANL), cofired over 550 tons of dRDF and bdRDF with a high sulfur Kentucky coal in a boiler at ANL. This work examines the emission rates of polychlorinated dioxins (PCDDs) and furans (PCDFs) during the combustion of the dRDF, bdRDF, and coal. Even at levels of 50% by Btu content of dRDF in the fuel feedstock, emission rates of PCDDs and PCDFs were below detection limits. The dRDF is shown to be an environmentally acceptable product, which could help resolve one of the major social and environmental problems facing this country today.

Driven by the fact that the global oil market has become extremely volatile and the EU dependence on oil continues to grow, this paper argues that with more emphasis on renewable energy and by using domestically produced alternative energy sources instead of importing foreign oil the EU Member States would drastically improve their energy security and energy independence. The study investigates both past and present trends in the EU energy sources supply and consumption patterns. Additionally, the paper considers possibilities of the renewable and alternative energy both at the current stage and future development of this sector in the EU. The research findings confirm the initial hypothesis as to whether the share of alternative and renewable energy will be sufficiently large to contribute to solving a problem of the EU energy security and independency. The role of the renewables in national energy security strategies of three EU Member States is studied and government supporting policies that enhance renewable sources development are analyzed.

Doctor of Philosophy / Department of Chemistry / Stefan H. Bossmann / Porin A from Mycobacterial smegmatis (MspA) is an octameric trans-membrane channel protein and is one of the most stable porins known to date. MspA has been successfully isolated and purified to obtain liquid extracts and crystals using a modified extraction procedure. A full analytical assessment has been carried out to authenticate its’ structure, including gel electrophoresis, spectroscopy (fluorescence, UV, FTIR, NMR), HPLC, Bradford protein assay, dynamic light scattering and X-ray crystallography. Nanoscopic vesicle formation of MspA molecules in aqueous media has been thoughroughly investigated. Temperature dependent dynamic light scattering experiments reveal that size of such vesicles is dependent on temperature but is independent of ionic strength of the medium. Zeta potential measurements reveal a steady build up of positive charge on the vesicle surface with increasing temperature. For the first time, wild type (WT) MspA has been utilized as a channel forming agent. This phenomenon has future potential in DNA sequencing and the development of antimycobacterial drugs. Channel activity of WT MspA and mutant A96C MspA has been investigated and has shown to form stable channels across DPhPC lipid bilayers. Blocking of the channel current via external molecules (i.e. channel blocking) is an extremely important process, which helps to evaluate the biosensor ability of the pore. In this regard, two Ruthenium based compounds, Ru(QP-C2)38+ (i.e. RuC2) and Ru(bpy)32+have been successfully employed as channel blocking agents. Both compounds show evidence for channel blocking of WT MspA. However, these results are not reproducible. Three dimensional aggregation behavior of RuC2-MspA vesicles have been thoughroughly investigated. It is evident that addition of RuC2 significantly increases vesicle size and polydispersity of MspA aggregates in solution. The results provide explanations onto the lack of channel blocking ability of MspA by RuC2. Development of a ‘greener’ dye sensitized solar cell with the use of MspA as an electron carrier is investigated for the first time. A series of Ru(II)-phenanthroline-based dyes have been synthesized as non-toxic dyes in this regard. Chemical binding between the dyes and MspA has been achieved successfully. Two types of solar cell prototypes, i.e. TiO2-based (Grätzel type) and FTO-based have been developed and tested. Significant current generation and conversion efficiencies have been achieved for both cell types. This marks the first development of a protein-based photovoltaic device, which has the potential to be developed as a new class of “hybrid soft solar cells”.

Master of Science / Department of Biological and Agricultural Engineering / Donghai Wang / Biomass torrefaction is an important preprocessing step in improving biomass quality, specifically in terms of physical properties and chemical composition. The objective of this research was to study effects of torrefaction as a pretreatment method on chemical and elemental compositions and thermal properties of Conservation Reserve Program (CRP) biomass. Most CRP grasslands are a mixture of native grasses, and in the state of Kansas, species including indiangrass, big bluestem, little bluestem, sideoats grama, and switchgrass comprise a majority of CRP grounds. Pure forms of big bluestem biomass were analyzed and compared with a mixture of the species that make up CRP lands. Two strategies for torrefaction were tested: one with a pre-dry step and one without. After torrefaction, big bluestem and CRP biomass showed an increase in energy density, making the biomass more attractive as a biofuel source than raw biomass. Big bluestem also showed slightly higher calorific values than that of CRP biomass. The torrefaction process had a significant effect on chemical composition and elemental composition of the biomass. Carbon content increased and oxygen content decreased as torrefaction temperature increased. Glucan and xylose decreased and lignin increased as torrefaction temperature increased. Pre-drying biomass before torrefaction is beneficial to torrefaction of biomass with high moisture content because moisture removal leads to less dry matter loss while maintaining the same calorific value.

Master of Science / Department of Agricultural Economics / Jeffery Williams / Ethanol has become an important source of energy for transportation purposes in the U.S. The majority of the feedstock for this ethanol is corn grain. The use of crop residues and perennial grasses has been proposed as an alternative feedstock for ethanol production using cellulosic conversion processes. Commercial scale production of cellulosic ethanol is still on the horizon. In the meantime a wide variety of studies examining both the technical and economic feasibility of cellulosic ethanol production have been conducted. This is the first study that combines both county level cellulosic feedstock production and farmer participation rates to determine the feasibility of supplying it to cellulosic ethanol plants. This research determines the economic feasibility of supplying cellulosic feedstocks to seven potential add-on cellulosic ethanol plants of 25 million gallons per year at seven existing starch ethanol plants in Kansas. The feedstocks considered are corn stover, sorghum stalks, wheat straw, and perennial switchgrass. A mixed integer programing model determines the amount and mix of cellulosic feedstocks that can be delivered to these plants over a range of plant-gate feedstock prices given transportation costs and farm-gate production costs or breakeven prices. The variable costs of shipping are subtracted from the difference between plant-gate price and farm-gate price to find savings to the plant. The objective function of the model minimizes transportation costs which in turn maximizes savings to the plant. The role switchgrass may have as a feedstock given various switchgrass production subsidies is examined. The results indicate the minimum plant-gate price that must be paid to feedstock producers for all plants to have enough cellulosic feedstocks is $75 per dry ton. Switchgrass feedstocks were only a minor portion of biomass supplied and used without a production subsidy. A Biomass Crop Assistance Program payment increased the supply of switchgrass more than other production subsidies.

Master of Science / Department of Biological and Agricultural Engineering / Wenqiao Yuan / Gasification is an efficient way to produce energy from biomass, which has significant positive impacts on the environment, domestic economy, national energy security, and the society in general. In this study, a lab-scale updraft biomass gasifier was designed, built, and instrumented for stable gasification using low-bulk density biomass. Related accessories, such as a biomass feeder, inlet air temperature controller, air injection nozzle, and tar cracking system, were also developed to enhance gasifier performance. The effect of operation parameters on gasifier performance was studied. Two operational parameters, including air flow rate and feed-air temperature, were studied on three sources of biomass: prairie hay, sorghum biomass, and wood chips. Results showed that higher air flow rate increased tar contents in syngas for all three types. It was also found that different biomasses gave significantly different tar contents, in the order of wood chips>sorghum biomass>prairie hay. Feed-air temperature did not have a significant effect on tar content in syngas except for prairie hay, where higher feed air temperature reduced tar. A statistical model was implemented to study differences on syngas composition. Results showed that different biomasses produced syngas with different high heating value, e.g., wood chips > prairie hay > sorghum biomass. CO composition also showed differences by feed air temperature and biomass, e.g. prairie hay>wood chips>sorghum biomass, but H[subscript]2 did not show significant differences by either biomass type or operating conditions. Moreover, because of the downstream problems caused by tars in syngas such as tar condensation in pipelines, blockage and machinery collapse, an in-situ tar cracking system was developed to remove tars in syngas. The tar cracking device was built in the middle of the gasifier’s combustion using gasification heat to drive the reactions. The in-situ system was found to be very effective in tar removal and syngas enhancement. The highest tar removal of 95% was achieved at 0.3s residence time and 10% nickel loading. This condition also gave the highest syngas HHV increment of 36% (7.33 MJ/m[superscript]3). The effect of gas residence time and Ni loading on tar removal and syngas composition was also studied. Gas residence of 0.2-0.3s and Ni loading of 10% were found appropriate in this study.

Nesta tese investiga-se e avalia-se a combustão direta da glicerina bruta e loira, co-produto e derivado, respectivamente, do processo de fabricação do biodiesel como alternativa de aproveitamento energético sustentável. Focaliza-se especialmente nos aspectos ambiental, técnico e econômico considerando as emissões, a transferência de calor associada e os aspectos operacionais como o eixo principal do estudo. Visa aumentar o conhecimento atual a respeito e contribuir para a melhoria das perspectivas da indústria do biodiesel e de uma parte da população. Para a combustão de glicerina bruta proveniente do processo de fabricação de biodiesel de sebo bovino desenvolveu-se um queimador tipo vórtice para glicerina bruta, avaliaram-se e quantificaram-se as emissões de óxidos de enxofre e nitrogênio, monóxido e dióxido de carbono, hidrocarbonetos totais, formaldeído, acetaldeído e acroleína, sendo também avaliados os efeitos mutagênicos potenciais dos gases produzidos. Da mesma forma foi estudada a composição físico-química, poder calorífico, decomposição térmica e a transferência de calor associada, além dos parâmetros operacionais da combustão, entre eles, a relação ar-combustível, temperatura de chama adiabática e o desempenho geral do processo para diferentes coeficientes de excesso de ar. Os ensaios foram desenvolvidos utilizando-se uma fornalha flamo tubular dotada de 12 câmaras calorimétricas e totalmente instrumentada com sensores de temperatura e sondas para análise contínua de gases em analisadores automáticos, fornecimento e controle de água de resfriamento e sistema de captação de dados em tempo real. Adicionalmente aos requisitos do estudo, foi necessário o desenvolvimento de sistemas e equipamentos auxiliares como a unidade de acondicionamento e alimentação de glicerina bruta e métodos de filtragem. Paralelamente, os efeitos mutagênicos e tóxicos foram avaliados sobre o bio-sensor Tradescantia (Clone KU-20), adaptando câmaras de intoxicação e técnicas de análise biológica desenvolvidas previamente. Os resultados foram processados, avaliados e comparados com as emissões e comportamento observado durante a combustão direta do óleo diesel, constatando-se que a combustão direta de glicerina bruta é um processo viável e suas emissões de CO, NOx, \'SO IND.2\' e HCT foram em média 39%, 75%, 69% e 38% respectivamente menores do que as do óleo diesel, porém o material particulado emitido pela glicerina bruta, e ainda mais pela loira, foi várias vezes superior do que com óleo diesel. Do mesmo modo, o nível de acroleína detectado no gás de combustão de glicerina bruta (214 ppbv) aparentemente não representa perigo para a população. Igualmente a energia produzida a partir da glicerina bruta resultou 61% e 58% mais barata do que com óleo diesel e glicerina loira respectivamente em condições semelhantes. No entanto, certamente verificou-se que a combustão de glicerina bruta é um processo tecnicamente mais complexo quando comparado com a dos combustíveis convencionais e evidenciou-se a necessidade de fazer um controle adequado das partículas emitidas para avançar no desenvolvimento do processo. Desta forma o presente estudo constitui-se em uma fonte importante de informação sobre a glicerina bruta e outros combustíveis similares para autoridades ambientais, indústrias e pesquisadores. / This thesis investigated and evaluated on the assessment of the direct combustion of crude and technical glycerin, by-product and derivative respectively of Brazilian biodiesel manufacture process, as an alternative of sustainable energy use. The main axis of the study were the environmental, technical and economical aspects, focusing in emissions, heat transfer and the operational parameters associated with the combustion of crude and technical glycerin. It aims to increase the knowledge on the matter and contribute to the improvement of the economic and environmental perspective of biodiesel industry and isolated populations. It was evaluated the combustion of crude glycerin from bovine tallow biodiesel and technical glycerin from soy biodiesel process. Due to commercial unavailability of a capable burner for burning glycerin, a swirl burner was developed for crude and technical glycerin combustion, but it was also used successfully in other alternative fuels as raw bovine tallow and diesel. Emissions of sulphur and nitrogen oxides, total hydrocarbons, carbon monoxide, carbon dioxide, formaldehyde, acetaldehyde and acrolein were analyzed and quantified. Similarly, the mutagenic potential of gases was evaluated, as well as the calorific power, thermal decomposition behavior, the associated heat transfer and fundamentals operational parameters such as adiabatic flame temperature, air-fuel ratio and others. A experimental technique for mutagenic and toxicological effects assessment of combustion gases was analyzed and standardized, as well as the calorific power, the associate heat transfer and fundamentals operational parameters. The study was developed using a fully instrumented flame tube furnace, a swirl burner, continuous gas analyzers, a chromatograph, a thermogravimetric analyzer, automatic data acquisition systems and other auxiliary equipment. The mutagenic potential of the combustion gases was studied on biosensor Tradescantia clone KU-20 assay, using chambers of intoxication and biological analytical techniques previously developed and others specially adapted. The results were compared with the performance of diesel at similar conditions and finding that the direct combustion of crude glycerin is a feasible process. In addition, the emissions of CO, NOx, \'SO IND.2\' and THC were 39%, 75%, 69% and 38% correspondingly smaller than those of diesel. The particulate matter emitted by crude glycerin combustion and even more, by technical glycerin, was several times higher than those emitted by the diesel. Also, the emission of acrolein detected in flue gas from crude glycerin (214 ppbv), apparently have not represents danger to the population. Simultaneously was observed that the energy produced from crude glycerin was 61% and 58% cheaper than the energy from diesel and technical glycerin respectively under similar conditions. But certainly, it was found that the crude glycerin combustion is a more complex process compared with the combustion of conventional fuels.

O lodo de esgoto é uma biomassa residual abundante em todo o mundo resultante do tratamento de esgotos, é constituído por uma grande diversidade de componentes orgânicos e inorgânicos, tornando complexo seu tratamento pelas estações de tratamento de esgotos. Em um cenário onde a produção de lodo tende a crescer nos últimos anos, devido ao aumento do número de esgotos tratados e as limitações dos meios de descarte existentes de lodo, leva a necessidade de rotas alternativas para o aproveitamento tecnológico desse resíduo, nesse contexto, o processo de pirólise representa uma tecnologia promissora que permite a produção de quatro frações com potencial energético: bio-óleo, aquosa, sólida e gasosa. Este artigo analisa sobre o aspecto científico e tecnológico o avanço da aplicação do processo de pirólise ao lodo residual doméstico como uma tecnologia alternativa para produção de compostos com fins energéticos. / Sewage sludge is an abundant biomass waste worldwide resulting from sewage treatment plants, consists of a wide variety of organic and inorganic components, making the complex treatment of sewage treatment plants. In a scenario where the sludge production tends to grow in recent years, due to the increased number of treated sewage and limitations of existing means of sludge disposal, leads to the need for alternative routes for the technological use of this waste, in this context, the pyrolysis process is a promising technology that allows production of four fractions with energetic potential: bio-oil, water, gas and solid. This article analyzes on the scientific and technological advancement aspect of the application of pyrolysis to domestic waste sludge as an alternative technology for the production of compounds for energy purposes process.